Where Cringely went from interesting to a risk to himself and others is where he refused to stay connected to reality.
I can relate: I start a lot of projects where I'm usually in over my head. But I always learn, sometimes learn a lot and some of those projects eventually do work out. But I don't have my ego invested in any project and I think that is one of the bigger differences, some stuff works and is obvious, some stuff could work and is not obvious, some stuff can't work but it is not obvious (to me at least) and some stuff simply can't work and it is obvious. The third category is where you lose the money, the second is where you make it, the dividing line between the two will give you Theranos, UBeam and Moller on one side of the line and CISCO on the other.